Method of holding diamonds for drilling



Aug. 15,1944. H. J. FOXON 2,355,

' METHOD OF HOLDING DIAMONDS FOR DRILLING Filed March 16, 1942 lnvenfoi Henr' James FoxOn, I 1

His Abtorrmy.

I Patented Aug. '15, 1944 I UNITED" A S ATENT. OFFICE,

Henry James Foxon, Wembley, ngland, assignor to Ge eral- Electric Compan acorporation of New orlt- 1 Y Applieation'March 1c, 1942; Serial No. 434,957

In Great Britain April 1 6, 1941 cicima 101. 22-202) My invention relates to the manufacture of at the bottom. The metal carrierl is a dished diamond dies. In such manufacture one stage disc slightly wider than the aperture or cavity '2 s ly consists in fixing the diamond tobe drilled and provided near its apex with-radial claws 'in a recess in a steel block or like holderso that "fingersi adapted/to grip the diamond. The subit lies over a perforation in the holder. The fix- '5 sidiary member 9 is a steel ring fitting easily into ing must be extremely firm and allow of no possithe aperture. bility that the diamond may move relatively to In assembling .the parts the carrieris placed the holder in subsequent operations; and the pm- I over the aperture;- the diamond '6 is held in the sition of the diamond relatively to the perforacenter of the carrier, between the claws, by neetion must be adjustable withzconsiderable acl 0 d1es I, one of which passes upwards through'the curacy. I perforation 3 and the other projects downwards' In-one common method, the diamond is held in from above. A plunger 8, whose end is; similar the recess between the points of two needles to the subsidiary member 9, is then brought one of which passes through the perforation; the down, so as'topress the carrier 4 into the aperholder is heated and liquid metal is poured into ture 2; at the same time, owing to the shape of the recess. At a suitable stage in the cooling of I the carrier,- the claws 5 grip the diamond firmly. the holder and metal, the added metal is rammed The plunger is then withdrawn and replaced by home by a press or the like. This last step is the member 9. necessary, because otherwise gas trapped in the Apiece l0 of suitable alloy or solder having a metal is apt toimperil the permanence of the 2 low melting point (that generally used in the fixing; but it is diificult to ensure that the diaknown method will serve), is then placed in the mond, supported only by the needles, does not ring .9, a nd the'whole assembly is introduced in-* shift during the step; Moreover sinc'e'the holderto the silica vessel l2, which is then evacuated. hasjto be heated, the diamond is apt to be, partly The assembly is then heated by high frequency 1 burned away. induction ,from a coil (not-shown) placed round An object of this invention is to provide an imthe vessel, so that the metal In melts' and flows proved method of fixing the diamond in the round the diamond. The assembly is then alholder; as well as a novel assembly for holding lowed to cool and removed from the vessel. the diamond. 3 r The holes II in the base of the claws of the According to the invention the diamond is carrier (see Figure 2) are provided inorder that fixed, by a method that does not require the rais the metal may easily flow through the carrier. ing of its temperature, into a carrier which fits They are placed so that the ring 9, when in place; closely into the aperture in the holder; thesaid leaves most of them uncovered. Metal passing carrier is introduced into the apertureythe asthrough the holes may get between the diamond sembly, to which may be added one or more suband the perforation I; but this does not matter sidiary members (for example as hereinafter dein 11; s ill ayay after t m is scribed), is introduced into an' evacuated sp a'ce; p plete. 1 E and liquid metal is introduced into the aperture In Figure 3 the concave side of the carrieris so that, when cold, it fixes the diamond firmly in f downwards. ispr'eferabl if the diamond is the holder. I q 7 7 40 relatively thick. If it is relatively thin, it may One method according to the invention will now be preferable t place th concave side upwards be described by way of example with reference to during the step shown m Figure 3, a v the accompa yi d a n wherein F 1 What I claim as new and desire tosecure by t holder at the carrier at b and Letters Patent cf the United states is: 1

a s bs d ary be t 0 e parts being it 1. The method oil-fixing an unperiorated diaunassembledf Figure 2 shows on a larger scale a 2' mond, preparatory to drilling it, in a holder hav- (plan view and side section of thesaid carrier m a, cavity therein and an-aperture communithe diamond fixed in it; Fleur? 3 shows an eating with said cavity, which comprises fitting elevation, partly in section, of these parts-imme-- the diamond. in a carrier member which firmly diately prior to their assembly; Figure 4 shows engages th periphery of th dia o d and fits an elevati n, p y in section, or-the assembly in securely in the cavity, clamping'the diamond be- Jhe evacuated space with the metal. that is to be tween opposed needles one of which extends v I?melted-imposition, but still unmelted. through the said aperture in the holder, moving The holder I is of the usual kind, being a steel the needles longitudinally to carry the diamond 1 disc with an aperture 2 having a perforation 3 into the cavity against theperiphery of the said aperture while pressing the said carrier member into engagement with the walls of the cavity to thereby center the diamond and firmly support it in place, withdrawing the said needles, and then which fits closely in said cavity, pressing said,

carrier into said cavity so that said claws grip the diamondand hold it firmlyin place therein in alignment with said aperture, placing the assembly in an evacuated space, and introducing molten metal into said cavity around said diamond to fix it in place and firmly hold the parts 01' the assembly together.

3. The method of fixing a diamond in a cavity in a holder also having a small aperture therein communicating with said cavity, preparatory to drilling the diamond, which comprises placing the,

diamond in an opening formed by the ends of radial claws at the center of a dished disc-like carriervwhich fits closely in said cavity, pressing said carrier into said cavity so that the rim of the carrier is flattened against the bottom of the cavity and said claws grip the diamond and hold it firmly in place therein in alignment with said a carrier member which fits opening at thecenter of 4 the diamond to hold it in aperture, placing the assembly in an evacuated space, and introducing molten metal into said cavity around said diamond to fix it in place and firmly hold the parts of the assembly together.

4. In an assembly for holding a diamond to be drilled, a holder having a cavity therein and a small aperture communicating with said cavity, closely in said cavity and grips said diamond to hold it firmly in place in said cavity, said carrier member comprising a disc having radial claws extending toward an the disc and gripping said opening in alignment with said aperture, and a cast metal filling in said cavity serving to encase the diamond and carrier and firmly hold the parts of the assembly together.

5. In an assembly for holding a diamond to be drilled, a holder having a, cavity therein and a small aperture communicating with said cavity, acarrier member which fits closely in said cavity and grips said diamond to hold it firmly in place in said cavity, said carrier member comprising a normally dished disc having radial claws extending toward an opening at the center of the disc and gripping the diamond to hold it in said opening in alignment with said aperture, and a cast metal filling in said cavity serving to encase the diamond and carrier and firmly hold th parts of the assembly together.

HENRY JAMES FOXON. 

